Adjustable choke for shotguns



C. M. GIBSON ADJUSTABLE CHOKE FOR SHOTGUNS April 4, 1939.

Filed Oct. .11, 1937 ATTO RN EYS Patented Apr. 4, w39

ADJUSTABLE onoxn non snorGpNs oxyde Gibson, Huntington, w. ya. Application October 11, 1937, Serial No. 168,482

1 Claim.

This invention relates to choke attachments for shotgun barrels and has for the primary object the provision oi a device of this character which may be readily adapted to a gun barrel and may be easily and quickly adjusted to provide variable sizes of chokes thereby permitting a person with a gun thus equipped to have the same advantages which are attainable by the use of a number of gun barrels each of a dierent choke.

With these and other objects in view, this invention consists in certain) novel features of construction, combination and arrangement of parts to be hereinafter more fully described and claimed.

For a complete understanding of my invention, reference is to be had to the following description and accompanying drawing, in which Figure 1 is a side elevation illustrating a choke attachment constructed in accordance with my invention.

Figure 2 is a vertical sectional view illustrating a choke attachment with a key adapted thereto for the adjustment thereof.

Figure 3 is a transverse sectional view taken on line 3 3 of Figure 2.

Figure 4 is an end view illustrating an adjusting collar.

Figure 5 is a side elevation, partly in section,

of the device showing a key adapted thereto and equipped with a scale;

'Figure 6 is a sectional view taken on the line tof Figure 5.

Referring in detail to the drawing, the numeral i indicates a fragmentary portion of a gun barrel having external screw threads 2 at the nozzle end thereof and on which is threaded a supporting sleeve 3. One end of the supporting sleeve 3 is internally screw threaded certain of said threads meshing with the threads 2 while the other threads are engaged by external screw threads of a choke sleeve supported by the sleeve 3. The free end of the choke sleeve is externally beveled, as shown at 5. The choke sleeve also has extending inwardly for a selected distance from its free end a plurality of slots 6 to permit contraction of the choke sleeve. The choke sleeve at the inner ends of the slots is provided with an external annular groove i for aiding in permitting the slotted portion of the choke sleeve to readily contract and expand when free. The supporting sleeve is provided internally with feed threads 8 to mesh with feed threads 9 formed on an adjusting collar l0. The adjusting collar is supported by the sleeve 3 and has its inner end provided with an internal bevel to engage the external bevel of the choke sleeve so that by rotating the adjusting collar in one direction the slotted portions of the choke sleeve will be caused to contract increasing the choke to the gun barrel and a rotation of the collar I0 in an opposite direction permits expansion of the slotted portions of the choke sleeve to decrease the choke to the gun barrel. The adjusting col-4 lar I0 has a series of notches Il to be engaged by a spring pressed dog l2 carried by the supporting sleeve 3 for the purpose of locking the adjusting collar in its various positions. The dog may ride into and out of the notches when manual force is applied to the adjusting collar. The dog i2 is carried by a leaf spring i3 and the latter is secured on the supporting sleeve 3 by a pin i4 which may act as a gun sight. To adjust the adjusting sleeve I0, or in other words, to rotate the latter in opposite directions, a tool i5 is provided which includes a knurled portion i6, and a portion Il to extend into the adjusting collar and carries a pin iadapted to engage with notches 20 formed in the adjusting collar whereby rotation of the knurled portion I6 with the pin i 8 in engagement with the notches 20, the adjusting collar will be accordingly rotated. A scale is provided on the knurled portion to aid a person in obtaining a desired adjustment or contraction of the choke sleeve.

A set bolt 2i is carried by the supporting sleeve and is turned in engagement with the choke sleeve to prevent accidental unthreading of the choke sleeve from the supporting sleeve. Ihe internal diameter of the unslotted portion of the choke sleeve is approximately the same as the internal diameter of the gun barrel.

In some instances it may be desirable that the tube d be made as an integral part of the gun barrel and the tube 3 then would thread onto a collar (not shown) provided on the gun barrel.

What is claimed is:

A choke attachment for gun barrels comprising a supporting sleeve internally threaded for coupling to the muzzle end of a shotgun barrel, a choke sleeve threaded in said supporting sleeve at that end of the latter which couples with the gun barrel,J the choke sleeve being longitudinally slotted beyond the threaded portion and extending nearly to the end of the supporting sleeve, the latter at the end remote from the threaded end being provided with coarse interior threads, an adjusting collar exteriorly threaded to engage said interior threads and beveled on the interior periphery to engage the adjacent end of 2 v @Neelie the choke sleeve 'which is exteriorly beveled, the adjusting collar extending beyond the supporting sleeve and being pepherally nillecl, e, pin threaded radially into the supporting sleeve from the outer surface thereof to function as a sight, a leaf spring lying at on the supporting sleeve and retained in position thereon by said pin, the spring extending in the direction of the length of the supporting sleeve, and e. dog carried by the spring at the end remote from the pin and passing through a. clearance opening in the supporting sleeve to engage notches formed et spaced points around the periphery of the adjusting ce1- lar to preclude rotation of the latter after adjustment, the spring allowing the dog to yield in the manuel adjustment of the coller.

CLYDE M. GON. 

